Hm yes perhaps too constructed but well that's not something easy to shake off. If anything I see a lot of blank expressions and few 'open-mouth' ones. I would suggest every time you draw a face before you start, think of a nuanced emotion you'd like to convey. Even if it's impossible to coney to the viewer just by a portrait ("well of course she's irritated because her cat pooped on the sofa, what else could she be with that face?!") you'd know if you failed or not. You seem to have face construction down fine enough to start telling emotional stories so why bother doing a full page of disembodied blank faces, you know?
If you want morphological advice, you seem to draw one type of lips almost exclusively, with some variable upper lip size from men to women. I'd try a few different things there. Also why not attempt a few less 'pleasant' faces, you know? Draw ugly people, but try to hit that place where they're ugly but look real, not like some grotesque judgment.